Predictive temperature scheduling for a thermostat using machine learning

ABSTRACT

A heating, ventilation, and air conditioning (HVAC) control device configured to receive a user input for controlling an HVAC system, to determine whether the user input indicates an energy saving occupancy setting, and to identify a first plurality of time entries that are associated with a confidence level for a predicted occupancy status that is less than a predetermined threshold value in the predicted occupancy schedule. The device is further configured to modify the predicted occupancy schedule by setting the first plurality of time entries to an away status when the user input indicates an aggressive energy saving occupancy setting. The device is further configured to modify the predicted occupancy schedule by setting the second plurality of time entries to a present status when the user input indicates a conservative energy saving occupancy setting. The device is further configured to output the modified predicted occupancy schedule.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/731,995 filed Dec. 31, 2019, by Sridhar Venkatesh et al., andentitled “PREDICTIVE TEMPERATURE SCHEDULING FOR A THERMOSTAT USINGMACHINE LEARNING,” which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to thermostat control for aheating, ventilation, and air conditioning (HVAC) system, and morespecifically to predictive temperature scheduling for a thermostat usingmachine learning.

BACKGROUND

Existing heating, ventilation, and air conditioning (HVAC) systemstypically rely on a user (e.g. a home owner) to provide schedulinginformation about when they will be home or away. However, some usersmay never provide this information to the HVAC system. Determiningwhether a home owner will be present or away without requiring the userto provide this information in advance poses several technicalchallenges because existing HVAC systems lack the capabilities todetermine this information on their own. Without this information, anHVAC system is unable to provide energy saving benefits, for examplereduced power consumption, and reduce the wear on its components becauseexisting HVAC system are unable to automatically adjust set pointtemperatures without knowing whether a user is present. In someinstances, it is not desirable for an HVAC system to make changes to aset point temperature while a user is present because these changes mayaffect the comfort level of the user.

SUMMARY

The system disclosed in the present application provides a technicalsolution to the technical problems discussed above by employing machinelearning to learn and predict the behavior and preferences of a user.The disclosed system provides several practical applications andtechnical advantages which include a process for leveraging otherdevices that a user interacts with to collect information about theuser's behavior and preferences. In one embodiment, the system comprisesa device that is configured to collect information about whether a useris present or away based on a location of their user device, a traveldirection for their user device, a network connection type that the useris using, their interactions with the thermostat, and their interactionswith other types of devices. The device is further configured tointerpolate and extrapolate the collected information to capture auser's behavior and preferences over some period of time. Thisinformation can then be used to generate or train a machine learningmodel to predict the user's behavior. This process improves theoperation of the HVAC system by enabling the system to learn about auser's behavior and preferences based on their actions, rather thanrelying on the user to provide this information.

The disclosed system also provides a process for generating a machinelearning model for predicting whether a user will be present or awayfrom a space. In one embodiment, the system comprises a device that isconfigured to generate a machine learning model that uses collected userinformation to generate a predicted occupancy schedule that predictswhether a home owner will be home or away at various times of the day.The device can use the predicted occupancy schedule to control the HVACsystem to provide energy savings by adjusting the set point temperaturewhile the home owner is away. This process improves the performance ofthe HVAC system by enabling the HVAC system to predict when a user willbe present or away so that the HVAC system can adjust a set pointtemperature to provide energy saving benefits and reduce the wear on thesystem's components.

The disclosed system also provides a process for conservatively oraggressively adjusting a predicted set point temperature to providedifferent levels of energy savings. In one embodiment, the systemcomprises a device that is configured to update a predicted occupancyschedule to use conservative or aggressive energy saving settings forcontrolling the HVAC system. The device may adjust values in thepredicted occupancy schedule to improve energy saving benefits. Forexample, the device may update a predicted occupancy schedule toincrease a cooling set point temperature to reduce the amount of energyconsumed by the HVAC system. The device may use historical informationfor a user which allows the device to select a suitable set pointtemperature that reduces energy consumption while keeping the usercomfortable. This process improves the performance of the HVAC system byenabling the HVAC system to offer a variety of energy saving settingswhich can further reduce power consumption and reduce the wear on thesystem's components.

The disclosed system also provides a process for correcting errors in apredicted occupancy schedule for a user. In one embodiment, the systemcomprises a device that is configured to periodically compare predictedoccupancy statuses and set point temperatures to actual occupancystatuses and set point temperatures to determine how accurately apredicted occupancy schedule follows the actual behavior of a user. Thedevice is configured to provide error correction to update the predictedoccupancy schedule when the predicted occupancy schedule deviates fromthe actual behavior of a user. This process improves the performance ofthe HVAC system by enabling the HVAC system to periodically update itspredictions on whether a user will be present or away. This process alsoimproves the performance of the HVAC system by improving the accuracy ofthe machine learning model to predict an occupancy schedule for a user.

Certain embodiments of the present disclosure may include some, all, ornone of these advantages. These advantages and other features will bemore clearly understood from the following detailed description taken inconjunction with the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in connection with theaccompanying drawings and detailed description, wherein like referencenumerals represent like parts.

FIG. 1 is a schematic diagram of heating, ventilation, and airconditioning (HVAC) control system configured to use machine learning;

FIG. 2 is a flowchart of an embodiment of a thermostat scheduling methodfor an HVAC system;

FIG. 3 is an example of an event data collecting process based on a userdevice location;

FIG. 4 is an example of an event data collecting process based on a userdevice travel direction;

FIG. 5 is an example of an event data collecting process based onnetwork connection types;

FIG. 6 is an example of an occupancy history log;

FIG. 7 is a flowchart of an embodiment of a predictive presencescheduling method for an HVAC system;

FIG. 8 is an example of a portion of a machine learning model forpredicting whether a user will be present;

FIG. 9 is an example of a predicted occupancy schedule;

FIG. 10 is an example of a process for determining an occupancy statususing a machine learning model;

FIG. 11 is a flowchart of an embodiment of a predictive temperaturescheduling method for an HVAC system;

FIG. 12 is an example of historical set point temperatures for a space;

FIG. 13 is another example of historical set point temperatures for aspace;

FIG. 14 is a flowchart of an embodiment of a predictive schedule errorcorrection method for an HVAC system;

FIG. 15 is an example of a process for identifying conflicting occupancystatuses;

FIG. 16 is a schematic diagram of an embodiment of a device configuredto control an HVAC system using machine learning; and

FIG. 17 is a schematic diagram of an embodiment of an HVAC systemconfigured to use machine learning.

DETAILED DESCRIPTION

Information System Overview

FIG. 1 is a schematic diagram of heating, ventilation, and airconditioning (HVAC) control system 100 that is configured to use machinelearning. In one embodiment, the HVAC control system 100 comprises acontroller 102, an HVAC system 104, a thermostat 106, and devices 108that are in signal communication with each other in a network 124.

The network 124 may be any suitable type of wireless and/or wirednetwork including, but not limited to, all or a portion of the Internet,an Intranet, a private network, a public network, a peer-to-peernetwork, the public switched telephone network, a cellular network, alocal area network (LAN), a metropolitan area network (MAN), a wide areanetwork (WAN), and a satellite network. The network 124 may beconfigured to support any suitable type of communication protocol aswould be appreciated by one of ordinary skill in the art.

The HVAC system 104 is generally configured to control the temperatureof a space 122. Examples of a space 122 include, but are not limited to,a room, a home, an office, or a building. The HVAC system 104 maycomprise a thermostat 106, compressors, blowers, evaporators,condensers, and/or any other suitable type of hardware for controllingthe temperature of the space 122 as would be appreciated by one ofordinary skill in the art. An example of an HVAC system 104configuration and its components is described below in FIG. 17 . TheHVAC system 104 comprises one or more thermostats 106 located within thespace 122. A thermostat 106 may be a single-stage thermostat, amulti-stage thermostat, or any suitable type of thermostat as would beappreciated by one of ordinary skill in the art. The thermostat 106 isconfigured to allow a user to select a desired temperature or set pointtemperature for the space 122. The controller 102 may use informationfrom the thermostat 106 such as the set point temperature forcontrolling a compressor and/or a blower. In one embodiment, thethermostat 106 and the controller 102 are integrated into a singledevice. In another embodiment, the thermostat 106 may be a device thatis external from the controller 102. In this example, the thermostat 106is in signal communication with the controller 102 using any suitabletype of wired or wireless communications.

An example of a hardware configuration for the controller 102 isdescribed in FIG. 16 . The controller 102 is generally configured tocontrol the operation of the HVAC system 104 using machine learning. Inone embodiment, the controller 102 is configured to collect event data114 from one or more devices 108 to generate a machine learning model112 for predicting an occupancy schedule and/or a set point temperatureschedule for the space 122. Examples of devices 108 include, but are notlimited to, computers, mobile devices (e.g. smart phones or tablets),user devices, Internet-of-things (IoT) devices, home automation devices,artificial intelligence (AI) devices, motion sensors, proximity sensors,or any other suitable type of device. An event is an action that istaken by a user that provides information to the controller 102 about auser's behavior or preferences. The event data 114 may comprise atimestamp 116 indicating a time when an event occurred, an occupancystatus 118 (e.g. a present status or an away status) for a user, a setpoint temperature 120, a source identifier that identifies a data source(e.g. a device identifier), a user identifier, a space identifier, orany other suitable type of information. An example of the controllerperforming this process is described below in FIG. 2 .

The controller 102 is further configured to generate a predictedoccupancy schedule 110 based on the event data 114 that is collectedfrom one or more devices 108. As an example, the controller 102 maygenerate a predicted occupancy schedule 110 that predicts whether a homeowner will be home or away at various times of the day. The controller102 can use the predicted occupancy schedule 110 to control the HVACsystem 104 to provide energy savings by adjusting the set pointtemperature while the home owner is away. An example of the controller102 performing this process is described below in FIG. 7 .

The controller 102 is further configured to update a predicted occupancyschedule 110 to use conservative or aggressive energy saving settingsfor controlling the HVAC system 104. The controller 102 may adjustoccupancy statuses 118 and/or set point temperature values 120 in thepredicted occupancy schedule 110 to improve energy saving benefits. Forexample, the controller 102 may update a predicted occupancy schedule110 to increase a cooling set point temperature to reduce the amount ofenergy consumed by the HVAC system 104. The controller 102 is configuredto use historical information for a user which allows the controller 102to select a suitable set point temperature that reduces energyconsumption while keeping the user comfortable. For instance, historicalinformation may comprise set point temperatures that a user haspreviously selected for the space 122 at various times of the year, forexample over the past couple of months or years. An example of thecontroller 102 performing this process is described below in FIG. 11 .

The controller 102 is further configured to perform error correction fora predicted occupancy schedule 110. For example, the controller 102 mayperiodically compare predicted occupancy statuses and set pointtemperatures to actual occupancy statuses and set point temperatures todetermine how accurately a predicted occupancy schedule 110 follows theactual behavior of a user. The controller 102 is configured to provideerror correction to update the predicted occupancy schedule 110 inresponse to determining that the predicted occupancy schedule 110 isdeviating from the actual behavior of a user. An example of thecontroller 102 performing this operation is described below in FIG. 14 .

In some embodiments, the controller 102 may be in signal communicationwith one or more remote data storage devices (e.g. servers, memories, ordatabases). In this case, the controller 102 may be configured to storethe predicted occupancy schedule 110, the machine learning model 112,and/or any other suitable type of data remotely in a remote data storagedevice. In some embodiments, the controller 102 may be configured toperform one or more of the processes described below (e.g. methods 200,700, 1100, and 1400) using remote computing or processing resources, forexample using cloud computing.

Thermostat Scheduling Process

FIG. 2 is a flowchart of an embodiment of a thermostat scheduling method200 for an HVAC system 104. The controller 102 may employ method 200 tocollect information about a user's behavior and habits for generating amachine learning model 112 that predicts whether the user will bepresent or away from a space 122 (e.g. a home) based on, for example,the day of the week and the time of the day. The collected informationalso trains the machine learning model 112 about what set pointtemperatures the user typically prefers when they are present in a space122. The controller 102 may employ method 200 to collect informationfrom a variety of devices 108 and to format the collected information sothat it can be used for training a machine learning model 112. Themachine learning model 112 can then be used to predict the user'sbehavior for scheduling and controlling a set point temperature for thespace 122.

At step 202, the controller 102 collects event data 114 from one or moredevices 108. The following are several non-limiting examples of how thecontroller 102 may collect event data 114 from other types of devices108.

Collecting Event Data Based on a User Device Location

As an example, the controller 102 may collect event data 114 based onhow far away a user device 108 (e.g. a mobile phone) is from the space122. For example, FIG. 3 illustrates a bird's eye view of the physicallocations of a space 122 and a user device 108. In this example, thecontroller 102 may determine a physical location 302 of a user device108 for a user. The physical location 302 of the user device 108 may bedescribed using Global Positioning System (GPS) coordinates or any othersuitable type of coordinate system. The controller 102 then determines adistance 306 (e.g. Euclidian distance) between the space 122 and thephysical location 302 of the user device 108. The controller 102compares the determined distance 306 between the space 122 and the userdevice 108 to a predetermined threshold value 308 that indicates amaximum distance away from the space 122 for the user to be associatedwith a present status. The predetermined threshold value 308 may set tothree hundred feet, eight hundred feet, one mile, five miles, or anyother suitable distance. When the controller 102 determines that thedistance 306 is less than the predetermined threshold value 308, thecontroller 102 determines that the user is present in the space 122. Inthis case, the controller 102 sets an occupancy status 118 in the eventdata 114 to a “present” or “home” status. When the controller 102determines that the distance 306 is greater than the predeterminedthreshold value 308, the controller 102 determines that the user is awayfrom the space 122. In this case, the controller 102 sets an occupancystatus 118 in the event data 114 to an away status. The controller 102may also set a timestamp 116 in the event data 114 with the current timein response to setting the occupancy status 118. In this example, thecollected event data 114 provides insight about when a user typicallyleaves and returns to a space 122.

Collecting Event Data Based on a User Device Travel Direction

As another example, the controller 102 may collect event data 114 basedon a determined travel direction of a user device 108. For example, FIG.4 illustrates a bird's eye view of the physical locations of a space 122and a user device 108. In this example, the controller 102 may determinea first physical location 402 of a user device 108 at a first timeinstance. The controller 102 then determines a first distance 404between the space 122 and the first physical location 402 of the userdevice 108. After some period of time, the controller 102 determines asecond physical location 406 of the user device 108 at a second timeinstance. The controller 102 then determines a second distance 408between the space 122 and the second physical location 406 of the userdevice 108. The controller 102 compares the first distance 404 at thefirst time instance to the second distance 408 at the second timeinstance to determine a travel direction for the user device 108 inrelation to time. The controller 102 determines that the user device 108is moving away from the space 122 when the second distance 408 isgreater than the first distance 404. For example, this scenario maycorrespond with when a user is driving away from their home. In thiscase, the controller 102 determines that the user is leaving the space122 and sets an occupancy status 118 in the event data 114 to an awaystatus. The controller 102 determines that the user device 108 is movingtowards the space 122 when the second distance 408 is less than thefirst distance 404. For example, this scenario may correspond with whena user is driving toward their home. In this case, the controller 102determines that the user approaching the space 122 and sets an occupancystatus 118 in the event data 114 to a present status. The controller 102may also set a timestamp 116 in the event data 114 with the current timein response to setting the occupancy status 118. In this example, thecollected event data 114 provides insight about when a user leaves andreturns to a space 122 based on travel direction.

Collecting Event Data Based on Thermostat Interactions

As another example, the controller 102 may collect event data 114 basedon a user's interactions with a thermostat 106. For instance, a user mayinteract with a thermostat 106 to provide a user input for a set pointtemperature. The user may interact with the thermostat 106 by physicallyinteracting (e.g. touching) with the thermostat 106 or by virtuallyinteracting with the thermostat 106 using a mobile application or webservice. In this example, the controller 102 sets a timestamp 116 in theevent data 114 with the current time in response to detecting that theuser provided the user input to the thermostat 106. The controller 102may set an occupancy status 118 in the event data 114 to a presentstatus in response to detecting that the user provided the user input tothe thermostat 106 by physically interacting with the thermostat 106. Inthis case, the controller 102 determines that the user was present inthe space 122 based on their physical interaction with the thermostat106 in the space 122. The controller 102 may set an occupancy status 118in the event data 114 to an away status in response to detecting thatthe user provided the user input to the thermostat 106 by virtuallyinteracting with the thermostat 106, for example via a web service (e.g.the Internet). In this case, the controller 102 may determine that theuser was not present in the space 122 based on how the user connects tothe thermostat 106. For instance, the controller 102 may determine thatthe user interacted with the thermostat 106 using an IP address or a WANconnection that is not associated with the space 122. The controller 102may also identify a set point temperature based on the user input (e.g.a requested set point temperature) and set a set point temperature value120 in the event data 114 to the identified set point temperature. Inthis example, the collected event data 114 provides insight abouttemperature preferences and when a user in present in a space 122 basedon their interactions with a thermostat 106. In other examples, thecontroller 102 may use a similar process to collect information forpredicting any other suitable type of indoor air parameter for the user.Examples of other indoor air parameters include, but are not limited to,humidity levels, Carbon Dioxide (CO₂) levels, or any other suitable typeof parameter.

Collecting Event Data Based on Presence Detection

As another example, the controller 102 may collect event data 114 basedon a user's interaction with a motion detector or proximity sensorlocated at the space 122. For instance, the controller 102 may receive asignal from a motion detector located at the space 122 in response to auser passing by the motion detector. The controller 102 determines thatthe user is present at the space 122 based on receiving the signal fromthe motion detector. The controller 102 may set a timestamp 116 in theevent data 114 with the current time in response to detecting the user.The controller 102 may set an occupancy status 118 in the event data 114to a present status in response to determining that the user is presentin the space 122. In this example, the collected event data 114 providesinsight about when a user is present in a space based detecting theirpresence within the space 122.

Collecting Event Data Based on Voice Commands

As another example, the controller 102 may collect event data 114 basedon a user's interaction with a device 108 (e.g. home automation device)to control a thermostat 106. For instance, a user may use voice commandsto instruct a home automation device 108 to set a set point temperatureon a thermostat 106. The controller 102 determines that the user ispresent at the space 122 based on detecting that the user has issued thevoice command to the home automation device 108 from within the space122. The controller 102 may set a timestamp 116 in the event data 114with the current time in response to detecting the user. The controller102 may set an occupancy status 118 in the event data 114 to a presentstatus in response to determining that the user is present in the space122. In this example, the collected event data 114 provides insightabout temperature preferences and when a user in present in a space 122based on their interactions with a thermostat 106 using home automationdevices.

Collecting Event Data Based on Network Connection Types

As another example, the controller 102 may collect event data 114 basedon changes in a network connection type for a user device 108. Forexample, FIG. 5 illustrates a bird's eye view of different networkconnection types with respect to the physical location of a space 122.In FIG. 5 , a user device 108 may be configured to use a networkconnection type corresponding with a LAN 502 that is associated with thespace 122 or a network connection type corresponding with a WAN 504 thatis not associated with the space 122. Examples of network connectionsfor a LAN 502 that is associated with the space 122 include, but are notlimited to, a WiFi network connection, a Bluetooth network connection, aZigbee network connection, a Z-wave network connection, or any othersuitable type of local network connection. Examples of networkconnections for a WAN 504 include, but are not limited to, a cellularnetwork connection and a satellite network connection.

In this example, the controller 102 determines a first networkconnection type for a user device 108 at a first time instance and thendetermines a second network connection type for the user device 108 at asecond time instance. For instance, the controller 102 may determine thesecond network connection type for the user device 108 after apredetermined amount of time has elapsed after the first time instance.The controller 102 then determines an occupancy status 118 based onchanges between the first network connection type and the second networkconnection type. The controller 102 sets the occupancy status 118 to apresent status when the first network connection type is associated witha WAN connection and the second network connection type is associatedwith a LAN connection for the space 122. This scenario corresponds withwhen a user approaches the space 122 and is close enough to switch froma WAN connection to a LAN connection for the space 122. The controller102 sets the occupancy status 118 to an away status when the firstnetwork connection is associated with a LAN connection for the space 122and the second network connection is associated with a WAN connection.This scenario corresponds with when a user is leaving the space 122 andhas to connect to a WAN connection because they are too far away to stayconnected to the LAN connection for the space 122. The controller 102may also set a timestamp 116 in the event data 114 with the current timein response to setting the occupancy status 118. In this example, thecollected event data 114 provides insight about when a user in presentin a space 122 based on changes in the network connection types.

Collecting Event Data Based on a LAN Connection

As another example, the controller 102 may collect event data 114 basedon whether a user device 108 for a user is connected to a LAN 502 thatis associated with a space 122. In this example, the controller 102 mayidentify one or more devices 108 that are currently connected to a LAN502 for a space 122. The controller 102 may use a device identifier(e.g. a MAC address and/or an IP address) to determine whether aparticular user device 108 for a user is among the one or more devices108 that are currently connected to the LAN 502 for the space 122. Inother words, the controller 102 checks to see whether a particular userdevice 108 is connected to the LAN 502 to determine whether the user ispresent in the space 122. The controller 102 sets the occupancy status118 in the event data 114 to a present status when the controller 102determines that the user device 108 is present among the devices 108that are currently connected to the LAN 502. The controller 102 sets theoccupancy status 118 in the event data 114 to an away status when thecontroller 102 determines that the user device 108 is not present amongthe devices 108 that are currently connected to the LAN 502. In thisexample, the collected event data 114 provides insight about temperaturepreferences and when a user in present in a space 122 based on detectingtheir presence using a LAN connection that is associated with the space122.

Returning to FIG. 2 at step 204, the controller 102 populates anoccupancy history log 602 (illustrated in FIG. 6 ) with the event data114 collected in step 202. Here, the controller 102 uses received eventdata 114 to fill in time entries 604 in an occupancy history log 602.The occupancy history log 602 describes the observed user behavior andpreferences based on the collected event data 114. Referring to FIG. 6as an example, an occupancy history log 602 comprises a plurality oftime entries 604 that are ordered chronologically. Each time entry 604may comprise a timestamp 116, a set point temperature 120, an occupancystatus 118, and/or any other suitable type of information. In thisexample, the timestamps 116 indicate an hour of a day. In otherexamples, the timestamps 116 may indicate a day of the week, a minute ofthe day, or any other suitable timing information. The controller 102uses timestamps 116 from the event data 114 to identify a correspondingtimestamp 116 in the occupancy history log 602 to fill in a time entry604 with event data 114. For example, the controller 102 may determinean event data 114 has a timestamp 116 that corresponds with 1:00 pm. Thecontroller 102 identifies a time entry 604 in the occupancy history log602 that corresponds with 1:00 pm and populates the time entry 604 withthe event data 114. In this example, the occupancy history log 602 usesBoolean values to indicate a present status or an away status. Forinstance, a Boolean value of one corresponds with a present status, anda Boolean value of zero corresponds with an away status.

Returning to FIG. 2 at step 206, the controller 102 determines whetherthere are any blank time entries 604 in the occupancy history log 602.For example, the collected event data 114 may be sparse data that doesnot provide information for every hour of the day. This means that afterthe controller 102 populates the occupancy history log 602 there may betime entries 604 that are unfilled or partially filled. For instance,one or more time entries 604 may contain timestamps 116 and occupancystatuses 118 but may not have a set point temperature value 120. In someinstances, one or more time entries 604 may not have any information.This may occur when the controller 102 is unable to collect event data114 at various time of the day. Here, the controller 102 determineswhether any of the time entries 604 are missing information and areblank or at least partially blank.

The controller 102 may terminate method 200 in response to determiningthat there are no blank time entries 604 in the occupancy history log602. In this case, the controller 102 determines that the occupancyhistory log 602 has been filled in completely and is ready to be usedfor other processes. The controller 102 proceeds to step 208 in responseto determining that there are blank time entries 604 in the occupancyhistory log 602. In this case, the controller 102 proceeds to step 208to begin the process of filling in any missing information for timeentries 604 in the occupancy history log 602.

At step 208, the controller 102 identifies blank time entries 604 in theoccupancy history log 602. Here, the controller 102 identifies any ofthe time entries 604 that are missing at least some information. At step210, the controller 102 populates the blank time entries 604 in theoccupancy history log 602 by forward filling the blank time entries 604with the most recent event data 114. For example, the controller 102 maydetermine that a time entry 604 is missing a set point temperature valueand an occupancy status. The controller 102 may use the set pointtemperature value and the occupancy status from a preceding time entry604 to fill in the missing set point temperature value and occupancystatus. As an example, the controller 102 may use values from a timeentry 604 for 12:00 pm to fill a time entry 604 for 1:00 pm.

After the controller 102 fills in any blank time entries 604, thecontroller 102 may store the completed occupancy history log 602 inmemory (e.g. memory 1604) or may use the completed occupancy history log602 to generate a machine learning model 112 using a process similar tothe process described below in FIG. 7 .

Predictive Presence Scheduling Process

FIG. 7 is a flowchart of an embodiment of a predictive presencescheduling method 700 for an HVAC system 104. The controller 102 mayemploy method 700 to generate a predicted occupancy schedule 110 thatpredicts whether a home owner will be home or away at various times ofthe day. The controller 102 can then use the predicted occupancyschedule 110 to control the HVAC system 104 to provide energy savings byadjusting the set point temperature while the home owner is away.

At step 702, the controller 102 obtains an occupancy history log 602.For example, the controller 102 may obtain the occupancy history log 602from memory (e.g. memory 1604) or from a process similar to the processdescribed above in FIG. 2 . The occupancy history log 602 comprises aplurality of occupancy statuses 118 over a predetermined amount of time.In some embodiments, the controller 102 may reformat the occupancyhistory log 602 into a suitable format for generating a machine learningmodel 112. For example, the occupancy history log 602 may containoccupancy statuses 118 that are associated with minutes of day insteadof hours of day. In this example, the controller 102 may reformat theoccupancy history log 602 to associate the occupancy statuses 118 withhours of the day. For instance, the controller 102 may determine whichoccupancy status 118 occurs most frequently with an hour. The controller102 may then associate the hour with an occupancy status 118 thatoccurred most frequently. In other embodiments, the controller 102reformat the occupancy history log 602 using any other suitabletechnique.

At step 704, the controller 102 generates a machine learning model 112based on the occupancy history log 602. In one embodiment, thecontroller 102 may analyze the occupancy history log 602 to determinewhether it contains enough data (e.g. occupancy statuses 118) forgenerating a machine learning model 112. The accuracy of a machinelearning model 112 depends on the quality and the quantity of data thatis used to train the machine learning model 112. This means that theaccuracy of a machine learning model 112 will degrade when there isinaccurate training data or an insufficient amount of training data. Forthis reason, the controller 102 may determine a number of occupancystatuses 118 in the occupancy history log 602. The controller 102 maythen compare the number of occupancy statuses 118 to a predeterminedthreshold value that corresponds with a minimum number of occupancystatuses 118 for generating a machine learning model 112. The controller102 may terminate method 200 when the number of occupancy statuses 118is less than the predetermined threshold value. In this case, thecontroller 102 determines that the occupancy history log 602 does notcontain a sufficient amount of data for generating a machine learningmodel 112. Otherwise, the controller 102 may proceed to generate amachine learning model 112 when the number of occupancy statuses 118 isgreater than the predetermined threshold value. In this case, thecontroller 102 determines that the occupancy history log 602 contains asufficient amount of data for generating a machine learning model 112.

In one embodiment, the controller 102 generates a machine learning model112 by performing a regression analysis using the data from theoccupancy history log 602 to train a set of weights for the machinelearning model 112. For example, the machine learning model 112 may berepresented as a linear or a non-linear function that includes aplurality of weights. At least a portion of the occupancy history log602 is used as training data to adjust weights, biases, or any othermachine learning model parameters while training and generating themachine learning model 112. For example, the controller 102 may performa regression analysis using the occupancy history log 602 to determine afirst set of weights for a machine learning model 112 that areassociated with a day of the week. The controller 102 may also use theoccupancy history log 602 to determine a second set of weights for themachine learning model 112 that are associated with a time of a day. Forexample, FIG. 8 shows an example of weights 802 for a machine learningmodel 112. In this example, weights 802A, 802B, and 802C are weights 802that are associated with a day of the week (e.g. Monday, Tuesday, andWednesday) and weights 802D and 802E are weights 802 associated with atime of the day (e.g. 1:00-2:00 pm and 2:00-3:00 pm). Each weight 802 ismultiplied by a variable 806 that corresponds with a day of the week(e.g. D_(mon), D_(tue), and D_(wed)), a time of the day (e.g. TS_(1-2PM)and TS_(2-3PM)), a temperature (e.g. a set point temperature), ahumidity level, a CO₂ level, or any other type of input. This variable806 can be used to select weights 802 for computing a probability 804.An example of this process is described below in step 708. Training themachine learning model 112 allows it to determine a probability 804 forwhether a user will be present at a space 122 based on a day of the weekand a time of the day. For example, the controller 102 can use themachine learning model 112 to determine a probability 804 for whether auser will be home at 2:00 pm on a Wednesday. In some cases, a differentportion of the occupancy history log 602 than the portion that is usedfor training the machine learning model 112 may be used as validationdata for testing the accuracy of the generated machine learning model112.

In one embodiment, the controller 102 may also use historical weatherinformation to generate the machine learning model 112. For example, thecontroller 102 may obtain historical weather information and determine athird set of weights 802 for the machine learning model 112 that areassociated with a temperature (e.g. a set point temperature) at a timeof a day. For instance, the controller 102 may access or requesthistorical weather information from a weather repository or database.The historical weather information may comprise previous local weathertemperatures at various times of the year. The historical weatherinformation may contain previous weather information for the previousmonth, the previous year, or from any other suitable time period. Inthis example, the machine learning model 112 may be configured to alsouse a forecasted weather temperature as an input. For example, thecontroller 102 also access or request forecasted weather informationfrom a weather repository or database. The forecasted weatherinformation comprises predicted local weather temperatures. Theforecasted weather information may contain forecasted weatherinformation for the next day, the next week, or any other suitable timeperiod. In other examples, the controller 102 may use any other suitabletype or combination of data to generate a machine learning model 112.

Returning to FIG. 7 at step 706, the controller 102 selects a time entry902 in a predicted occupancy schedule 110. Referring to FIG. 9 as anexample, the predicted occupancy schedule 110 comprises a plurality oftime entries 902 that each correspond with a day of the week and a timeof the day. The controller 102 may iteratively select time entries 902from the predicted occupancy schedule 110 to begin filling in timeentries 902 with a predicted occupancy status 904. For example, thepredicted occupancy schedule 110 indicates that space 122 is occupied at7 am on Tuesday (as indicated by the “1” in the corresponding entry902), but not occupied at Sam on Tuesday (as indicated by the “0” in thecorresponding entry 902). Furthermore, the predicted occupancy schedule110 indicates that space 122 is again occupied at 6 pm on Tuesday. Thispredicted occupancy schedule 110 therefore demonstrates a pattern ofnon-occupancy of the space 122 from 8 am through 6 pm on Tuesday, whichmay be indicative of a user that works away from the home during normaldaytime work hours. In contrast, the predicted occupancy indicates thatspace 122 is occupied all day on both Saturday and Sunday, whichdemonstrates a pattern of occupancy of the space 122 that may beindicative of a user that stays home on the weekends.

Returning to FIG. 7 at step 708, the controller 102 determines aprobability 804 of a present status for the selected time entry 902using the machine learning model 112. Referring to FIG. 10 as anexample, the controller 102 may use Boolean values to select the weights802 for computing the probability 804 of a present status for theselected time entry 902 using the machine learning model 112 describedin FIG. 8 . Previously in FIG. 8 , each weight 802 is multiplied by avariable 806 (e.g. D_(mon)) that corresponds with a day of the week, atime of the day, a temperature, or any other type of input. By setting avariable 806 to either a “1” or a “0,” the controller 102 can selectweights 802 for determining a probability 804. Setting a variable to “0”multiplies a weight 802 by zero and effectively removes the weight 802from a probability calculation. Setting a variable to “1” multiples aweight 802 by one and preserves the weight 802 for a probabilitycalculation. As an example, the selected time entry 902 may correspondwith Monday at 1:00-2:00 pm. In this example, the controller 102 may usea Boolean value of one to select the variables for the weights 802corresponding with Monday at 1:00-2:00 pm. The controller 102 may use aBoolean value of zero to ignore weights 802 corresponding with otherdays and times. FIG. 10 illustrates the remaining weights 802 afterselecting the appropriate weights 802 using Boolean values. Thecontroller 102 then determines the probability 804 that the user inpresent at the space 122 for the selected time entry 902 using theremaining weights 802 similar to as shown in FIG. 10 .

Returning to FIG. 7 at step 710, the controller 102 sets a predictedoccupancy status 904 for the selected time entry 902 based on theprobability 804 of a present status. In one embodiment, the controller102 sets a predicted occupancy status 904 to a present status when themachine learning model 112 outputs a probability 804 that is greaterthan or equal to 50%. In other examples, the controller 102 may set thepredicted occupancy status 904 to a present status when the machinelearning model 112 outputs a probability 804 that is greater than orequal 60%, 75%, or any other suitable percentage. Returning to theexample in FIG. 9 , the controller 102 may use a Boolean value toindicate a predicted occupancy status 904 for a particular time slot902. In this example, a Boolean value of one corresponds with a presentstatus (i.e. the user is home) and a Boolean value of zero correspondswith an away status (i.e. the user is away). In other examples, thecontroller 102 may use any other suitable value to represent a presentstatus and an away status. In some embodiments, the controller 102 mayalso associate the selected time entry 902 with a confidence level thatcorresponds with the probability 804 for the predicted occupancy status904.

In some embodiments, the controller 102 may also associate the selectedtime entry 902 with a heating set point temperature and/or a cooling setpoint temperature. A heating set point temperature is a predicted setpoint temperature for a space 122 when an HVAC system 104 is operatingin a heating mode. A cooling set point temperature is a predicted setpoint temperature for a space 122 when an HVAC system 104 is operatingin a cooling mode. The controller 102 may determine a cooling set pointtemperature or a heating set point temperature based on the occupancyhistory log 602. For example, the controller 102 may identify a coolingset point temperature or a heating set point temperature from theoccupancy history log 602 that corresponds with the selected time entry902. For example, the controller 102 may select a time entry 902 thatcorresponds with Friday at 7:00 pm. The controller 102 may look for setpoint temperatures in the occupancy history log 602 that correspond withFriday at 7:00 pm. The controller 102 uses the information from theoccupancy history log 602 to determine what set point temperature theuser typically prefers at this time and then associates the determinedset point temperature with the selected time entry 902. Returning toFIG. 7 at step 712, the controller 102 determines whether the predictedoccupancy schedule 110 is complete. Here, the controller 102 determineswhether a predicted occupancy status 904 has been set for all of thetime entries 902 in the predicted occupancy schedule 110. The controller102 determines that the predicted occupancy schedule 110 is incompletewhen one or more time entries 902 do not have a predicted occupancystatus 904. The controller 102 determines that the predicted occupancyschedule 110 is complete when all of the time entries 902 have apredicted occupancy status 904. The controller 102 returns to step 706in response to determining that the predicted occupancy schedule 110 isnot complete. Here, the controller 102 returns to step 706 to selectanother time entry 902 from the predicted occupancy schedule 110 to fillin with a predicted occupancy status 904. Otherwise, the controller 102proceeds to step 714 in response to determining that the predictedoccupancy schedule 110 is complete.

At step 714, the controller 102 outputs the completed predictedoccupancy schedule 110. In one embodiment, the controller 102 may outputthe predicted occupancy schedule 110 by storing the predicted occupancyschedule 110 in a memory (e.g. memory 1604). In one embodiment, thecontroller 102 may output the completed predicted occupancy schedule 110by presenting the predicted occupancy schedule 110 to a user on agraphical user interface. In this example, the controller 102 maypresent the predicted occupancy schedule 110 to a user to confirmwhether the user accepts the predicted occupancy schedule 110. In theevent that the user does not accept the predicted occupancy schedule110, the controller 102 may repeat the process described in method 700using a different set of training data (e.g. a different portion of theoccupancy history log 602) to generate a different predicted occupancyschedule 110.

In one embodiment, the controller 102 may output the predicted occupancyschedule 110 by using the predicted occupancy schedule 110 to control anHVAC system 104. For example, the controller 102 or the thermostat 106may use the predicted occupancy schedule 110 for setting present andaway statuses and/or for controlling a set point temperature for an HVACsystem 104 based on predicted occupancy statuses 904.

Predictive Temperature Scheduling Process

FIG. 11 is a flowchart of an embodiment of a predictive temperaturescheduling method 1100 for an HVAC system 104. The controller 102 mayemploy method 1100 to update a predicted occupancy schedule 110 to useconservative or aggressive energy saving settings for controlling theHVAC system 104. The controller 102 may adjust occupancy statuses and/orset point temperatures in the predicted occupancy schedule 110 toimprove energy saving benefits. For example, the controller 102 mayupdate a predicted occupancy schedule 110 to increase a cooling setpoint temperature to reduce the amount of energy consumed by the HVACsystem 104. The controller 102 uses historical information for a userfor adjusting a set point temperature which allows the controller 102 toselect a suitable set point temperature that reduces energy consumptionwhile keeping the user comfortable.

At step 1102, the controller 102 obtains a predicted occupancy schedule110 for a space 122. For example, the controller 102 may obtain apredicted occupancy schedule 110 from memory (e.g. memory 1604) or fromthe process described above in FIG. 7 . The predicted occupancy schedule110 comprises a plurality of time entries 902 that are each associatedwith a day of the week and an hour of a day. Each time entry 902 may beassociated with a predicted occupancy status 904 (e.g. a present statusor an away status), a heating set point temperature, a cooling set pointtemperature, a confidence level for the predicted occupancy status 904,a confidence level for a heating set point temperature, and/or aconfidence level for a cooling set point temperature.

At step 1104, the controller 102 receives a user input for an HVACsystem 104. In one embodiment, the user may provide a user input byphysically or virtually interacting with a thermostat 106 and/or thecontroller 102. The user input may comprise instructions for anoccupancy setting, a heating set point temperature setting, and/or acooling set point temperature setting. For example, the user input maycomprise an occupancy setting that indicates whether the user wants toconfigure the HVAC system 104 to use conservative or aggressive energysaving occupancy settings. When the HVAC system 104 is configured for aconservative energy saving occupancy setting, the controller 102 mayassume that a user is home when the controller 102 is uncertain about anoccupancy status 118 for the space 122. When the HVAC system 104 isconfigured for an aggressive energy saving occupancy setting, thecontroller 102 may assume that the user is away when the controller 102is uncertain about an occupancy status 118 for the space 122.

As another example, the user input may comprise a heating setting (e.g.a heating set point temperature setting) that indicates whether the userwants to configure the HVAC system 104 to use conservative or aggressiveheating set point temperature settings. When the HVAC system 104 isconfigured for a conservative heating set point temperature setting, thecontroller 102 may use the highest historical heating set pointtemperature for the space 122 as the set point temperature for the space122. When the HVAC system 104 is configured for an aggressive heatingset point temperature setting, the controller 102 may use the lowesthistorical heating set point temperature for the space 122 as the setpoint temperature for the space 122.

As another example, the user input may comprise a cooling setting (e.g.a cooling set point temperature setting) that indicates whether the userwants to configure the HVAC system 104 to use conservative or aggressivecooling set point temperature settings. When the HVAC system 104 isconfigured for a conservative cooling set point temperature setting, thecontroller 102 may use the lowest historical cooling set pointtemperature for the space 122 as the set point temperature for the space122. When the HVAC system 104 is configured for an aggressive coolingset point temperature setting, the controller 102 may use the highesthistorical cooling set point temperature for the space 122 as the setpoint temperature for the space 122.

At step 1106, the controller 102 determines whether the user inputprovides instructions for an occupancy setting. The controller 102proceeds to step 1108 in response to determining that the user inputprovides instructions for an occupancy setting. At step 1108, thecontroller 102 determines whether the user input indicates an aggressiveenergy saving occupancy setting. The controller 102 proceeds to step1110 in response to determining that the user input does not indicate anaggressive energy saving occupancy setting. In other words, thecontroller 102 proceeds to step 1110 in response to determining that theuser input indicates a conservative energy saving occupancy setting.

At step 1110, the controller 102 configures the HVAC system 104 to use aconservative predicted occupancy schedule 110. In this case, thecontroller 102 may identify time entries 902 in the predicted occupancyschedule 110 that are associated with a confidence level that is lessthan a predetermined threshold value. The predetermined threshold valuecorresponds with a minimum confidence level for the controller 102 to beconfident with the predicted occupancy status 904. The controller 102may modify or set the predicted occupancy statuses 904 for the timeentries 902 that are associated with a confidence level that is lessthan the predetermined threshold to a present status. In thisconfiguration, the controller 102 may assume that a user is home whenthe controller 102 is uncertain about an occupancy status 118 for thespace 122. Execution then proceeds to step 1114.

Returning to step 1108, the controller 102 proceeds to step 1112 inresponse to determining that the user input indicates an aggressiveenergy saving occupancy setting. At step 1112, the controller 102configured the HVAC system 104 to use an aggressive predicted occupancyschedule 110. In this case, the controller 102 may identify time entries902 in the predicted occupancy schedule 110 that are associated with aconfidence level that is less than the predefined threshold value thatwas described in step 1110. The controller 102 may modify or set thepredicted occupancy statuses 904 for the time entries 902 that areassociated with a confidence level that is less than the predeterminedthreshold to an away status. In this configuration, the controller 102may assume that a user is away when the controller 102 is uncertainabout an occupancy status 118 for the space 122. Execution then proceedsto step 1114.

Returning to step 1106, execution proceeds to step 1114 in response todetermining that the user input does not provide instructions for anoccupancy setting. At step 1114, the controller 102 determines whetherthe user input provides instructions for a heating set point temperaturesetting. The controller 102 proceeds to step 1116 in response todetermining that the user input provides instructions for a heating setpoint temperature setting. At step 1116, the controller 102 determineswhether the user input indicates an aggressive energy saving heating setpoint temperature setting. The controller 102 proceeds to step 1118 inresponse to determining that the user input does not indicate anaggressive energy saving heating set point temperature setting. In otherwords, the controller 102 proceeds to step 1118 in response todetermining that the user input indicates a conservative energy savingheating set point temperature setting.

At step 1118, the controller 102 configured the HVAC system 104 to use aconservative heating set point temperature schedule. In this case, thecontroller 102 obtains historical set point temperature information 1202for the space 122. Historical set point temperature information 1202 maycomprise a log or history of heating set point temperatures and coolingset point temperatures for a space 122 over some period of time (e.g.weeks, months, or years). For example, FIG. 12 illustrates a histogramfor a range of heating set point temperatures for a space 122 and thenumber of instances that a heating set point temperature was used oversome period of time. The controller 102 identifies the highest heatingset point temperature from among the range of heating set pointtemperatures for the space 122. In this example, the controller 102selects a heating set point temperature of sixty-nine degrees. Thecontroller 102 then identifies time entries 902 in the predictedoccupancy schedule 110 that are associated with a heating set pointtemperature confidence level that is less than a predetermined thresholdvalue. The controller 102 modifies or sets the identified time entries902 to use the identified highest heating set point temperature. In thisconfiguration, the controller 102 configured the HVAC system 104 to usea conservative heating set point temperature that is still within therange of suitable temperatures for the space 122. Execution thenproceeds to step 1122 of FIG. 11 .

Returning to FIG. 11 at step 1116, the controller 102 proceeds to step1120 in response to determining that the user input indicates anaggressive energy saving heating set point temperature setting. At step1120, the controller 102 configured to the HVAC system 104 to use anaggressive heating set point temperature schedule. In this case, thecontroller 102 obtains historical set point temperature information 1202for the space 122. Referring again to FIG. 12 as an example, thecontroller 102 identifies the lowest heating set point temperature fromamong the range of heating set point temperatures for the space 122. Inthis example, the controller 102 selects a heating set point temperatureof sixty-four degrees. The controller 102 then identifies time entries902 in the predicted occupancy schedule 110 that are associated with aheating set point temperature confidence level that is less than apredetermined threshold value. The controller 102 modifies or sets theidentified time entries 902 to use the identified lowest heating setpoint temperature. In this configuration, the controller 102 configuredthe HVAC system 104 to use an aggressive heating set point temperaturethat is still within the range of suitable temperatures for the space122. Execution then proceeds to step 1122.

Returning to FIG. 11 at step 1114, execution proceeds to step 1122 inresponse to determining that the user input does not provideinstructions for a heating set point temperature setting. At step 1122,the controller 102 determines whether the user input providesinstructions for a cooling set point temperature setting. The controller102 proceeds to step 1124 in response to determining that the user inputprovides instructions for a cooling set point temperature setting. Atstep 1124, the controller 102 determines whether the user inputindicates an aggressive energy saving cooling set point temperaturesetting. The controller 102 proceeds to step 1126 in response todetermining that the user input does not indicate an aggressive energysaving cooling set point temperature setting. In other words, thecontroller 102 proceeds to step 1118 in response to determining that theuser input indicates a conservative energy saving cooling set pointtemperatures setting.

At step 1126, the controller 102 configures the HVAC system 104 to use aconservative cooling set point temperature setting. In this case, thecontroller 102 obtains historical set point temperature information 1202for the space 122. For example, FIG. 13 illustrates a histogram for arange of cooling set point temperatures for a space 122 and the numberof instances that a cooling set point temperature was used over someperiod of time. The controller 102 identifies the lowest cooling setpoint temperature from among the range of cooling set point temperaturesfor the space 122. In this example, the controller 102 selects a coolingset point temperature of seventy-three degrees. The controller 102 thenidentifies time entries 902 in the predicted occupancy schedule 110 thatare associated with a cooling set point temperature confidence levelthat is less than a predetermined threshold value. The controller 102modifies or sets the identified time entries 902 to use the identifiedlowest cooling set point temperature. In this configuration, thecontroller 102 configured the HVAC system 104 to use a conservativecooling set point temperature that is still within the range of suitabletemperatures for the space 122.

Returning to FIG. 11 at step 1124, the controller 102 proceeds to step1128 in response to determining that the user input indicates anaggressive energy saving cooling set point temperature setting. At step1128, the controller 102 configures the HVAC system 104 to use anaggressing cooling set point temperature setting. In this case, thecontroller 102 obtains historical set point temperature information 1202for the space 122. Referring again to FIG. 13 as an example, thecontroller 102 identifies the highest cooling set point temperature fromamong the range of cooling set point temperatures for the space 122. Inthis example, the controller 102 selects a cooling set point temperatureof eighty-one degrees. The controller 102 then identifies time entries902 in the predicted occupancy schedule 110 that are associated with acooling set point temperature confidence level that is less than apredetermined threshold value. The controller 102 modifies or sets theidentified time entries 902 to use the identified highest cooling setpoint temperature. In this configuration, the controller 102 configuredthe HVAC system 104 to use an aggressive cooling set point temperaturethat is still within the range of suitable temperatures for the space122.

In one embodiment, the controller 102 may output the modified predictedoccupancy schedule 110 by storing the modified predicted occupancyschedule 110 in a memory (e.g. memory 1604). In one embodiment, thecontroller 102 may output the modified predicted occupancy schedule 110by presenting the modified predicted occupancy schedule 110 to a user ona graphical user interface. In this example, the controller 102 maypresent the modified predicted occupancy schedule 110 to a user toconfirm whether the user accepts the modified predicted occupancyschedule 110.

In one embodiment, the controller 102 may output the modified predictedoccupancy schedule 110 by using the modified predicted occupancyschedule 110 to control an HVAC system 104. For example, the controller102 or the thermostat 106 may use the modified predicted occupancyschedule 110 for setting present and away statuses and/or forcontrolling a set point temperature for an HVAC system 104 based onmodified predicted occupancy statuses 904. At this point, executionterminates.

Error Correction Process

FIG. 14 is a flowchart of an embodiment of a predictive schedule errorcorrection method 1400 for an HVAC system 104. The controller 102 mayemploy method 1400 to periodically compare predicted occupancy statusesand set point temperatures to actual occupancy statuses and set pointtemperatures to determine how accurately a predicted occupancy schedule110 follows the actual behavior of a user. The controller 102 employsmethod 1400 to provide error correction to update the predictedoccupancy schedule 110 when the predicted occupancy schedule 110 isdeviating from the actual behavior of a user.

At step 1402, the controller 102 records actual occupancy statuses 1502within a predetermined time period. For example, the controller 102 maykeep a log of when a user is actually present or away from the space 122over the past three weeks. In other examples, the controller 102 mayrecord when a user is actually present or away from the space 122 overthe past week, the past month, the past two months, or any othersuitable time period. For example, FIG. 15 illustrates actual occupancystatuses 1502 for a user on a Monday between 8:00 am and 7:00 pm.

In some embodiments, the controller 102 may be configured to determinewhether the forecasted local weather over the predetermined time periodwill be similar to the weather historically over this same time periodbefore recording actual occupancy statuses 1502. The controller 102 mayterminate method 1400 when the forecasted weather is expected to deviatefrom normal weather behavior because a user's behavior may deviateduring these conditions. As an example, the controller 102 may obtainforecasted weather information for a location that is associated with aspace 122. The forecasted weather information identifies forecastedweather temperatures for one or more days. The controller 102 alsoobtains historical weather information for the location associated withthe space 122 for the same time period from previous years. Thecontroller 102 compares the forecasted weather information to thehistorical weather information to determine a temperature difference.For instance, if the forecasted high temperature for Monday is eightydegrees and the historical high temperature for Monday at the same timeof the year is eighty-two degrees, then the controller 102 may determinea temperature difference of two degrees between the forecasted weatherinformation and the historical weather information. The controller 102may then compare the determined temperature difference to a predefinedtemperature range to determine whether the forecasted weather is withina suitable temperature range before proceeding to step 1404. Thepredefined temperature range may be two degrees, three degrees, fivedegrees, or any other suitable temperature range. In some embodiments,the controller 102 may also consider rain, snow, or any other suitableweather condition before recording actual occupancy statuses 1502. Forexample, the controller 102 may determine to terminate method 1400 whenrain or snow are forecasted.

Returning to FIG. 14 at step 1404, the controller 102 determinespredicted occupancy statuses 1504 within the predetermined time period.Here, the controller 102 may use information from a predicted occupancyschedule 110 to determine predicted occupancy statuses 1504 thatcorrespond with the actual occupancy statuses 1502. For example, thecontroller 102 may use timestamps for the actual occupancy statuses 1502to identify predicted occupancy statuses 1504 with a correspondingtimestamp in the predicted occupancy schedule 110. Returning to theexample in FIG. 15 , the controller 102 may determine predictedoccupancy statuses 1504 that correspond with the actual occupancystatuses 1502 for a user on a Monday between 8:00 am and 7:00 pm.

Returning to FIG. 14 at step 1406, the controller 102 identifiesconflicting occupancy statuses 1506 between the actual occupancystatuses 1502 and the predicted occupancy statuses 1504. A conflictingoccupancy status 1506 indicates a difference between an actual occupancystatus 1502 and a predicted occupancy status 1504. The controller 102may identify conflicting occupancy statuses 1506 by comparing the actualoccupancy statuses 1502 to the predicted occupancy statuses 1504.Returning to the example in FIG. 15 , the controller 102 identifiesconflicting occupancy statuses between 12:00 am and 2:00 pm. In thisexample, the predicted occupancy status 1504 predicted that the userwould be away from the space 122 during this time, however, the actualoccupancy status 1502 shows that the user was present at the space 122during this time.

In some embodiments, the controller 102 may be configured to ignorecertain days when identifying conflicting occupancy statuses 1506. Forexample, the controller 102 may ignore weekends and/or holidays whenidentifying conflicting occupancy statuses 1506. In this case, thecontroller 102 may ignore these days due to their unique or widelyvarying behavior patterns for a user.

In some embodiments, the controller 102 may graphically presentconflicting occupancy statuses 1506 to a user. For example, thecontroller 102 may generate a heat map that overlays the conflictingoccupancy statuses 1506 with a predicted occupancy schedule 110. Thisallows a user to quickly identify when the conflicting occupancystatuses 1506 occurred. In other examples, the controller 102 maygraphically present conflicting occupancy statuses 1506 to a user usingany other suitable technique.

Once the controller 102 identifies one or more conflicting occupancystatuses 1506, the controller 102 will correct the predicted occupancyschedule 110 using previously stored occupancy historical information.In some embodiments, the controller 102 may be configured to onlycorrect conflicting occupancy statuses 1506 when the number ofconflicting occupancy statuses 1506 exceeds a predetermined thresholdvalue. The predetermined threshold value corresponds with a maximumnumber of allowed conflicting occupancy statuses 1506 for a predictedoccupancy schedule 110. When the number of conflicting occupancystatuses 1506 is less than the predetermined threshold value, this mayindicate that the conflicting occupancy statuses 1506 may be outliersand the controller 102 does not need to correct these conflictingoccupancy statuses 1506. However, when the number of conflictingoccupancy statuses 1506 exceeds the predetermined threshold value, thismay indicate that the predicted occupancy schedule 110 is deviating fromthe actual behavior of a user.

Returning to FIG. 14 at step 1408, the controller 102 selects aconflicting occupancy status 1506. Here, the controller 102 iterativelyselects a conflicting occupancy status 1506 from among the identifiedconflicting occupancy statuses 1506 to correct. At step 1410, thecontroller 102 determines a historical occupancy status 1508corresponding with the selected conflicting occupancy status 1506. Thecontroller 102 may obtain historical occupancy statuses 1508 from anoccupancy history log 602. For example, the controller 102 may identifya timestamp corresponding with the conflicting occupancy status 1506 andthen use the timestamp to identify historical occupancy statuses 1508from an occupancy history log 602. Returning to the example in FIG. 15 ,the controller 102 may identify a timestamp that corresponds with Mondayat 12:00 am for a conflicting occupancy status 1506. The controller 102may use the same timestamp (i.e. Monday at 12:00 am) to identifyhistorical occupancy statuses 1508 from an occupancy history log 602.

In some instances, the controller 102 may identify multiple historicaloccupancy statuses 1508 corresponding with the selected conflictingoccupancy status 1506. In this case, the controller 102 may usewhichever occupancy status occurs most often as the historical occupancystatus 1508. For example, the controller 102 may determine a percentageor a number of present statuses that occur within the multiplehistorical occupancy statuses 1508 corresponding with the selectedconflicting occupancy status 1506. In this example, the controller 102may determine that the historical occupancy status 1508 is a presentstatus when the determined percentage is greater than fifty percent. Thecontroller 102 may determine that the historical occupancy status 1508is an away status when the determined percentage is less than fiftypercent. The controller 102 may also use any other suitable percentagevalue for determining an historical occupancy status 1508. In otherexamples, the controller 102 may determine the historical occupancystatus 1508 using any other suitable technique.

Returning to FIG. 14 at step 1412, the controller 102 identifies a timeentry 902 in the predicted occupancy schedule 110 corresponding with theconflicting occupancy status 1506. The controller 102 may uses the sametimestamp that is used in step 1410 to identify a corresponding timeentry 902 in the predicted occupancy schedule 110. Continuing with theprevious example, the controller 102 may use a timestamp thatcorresponds with Monday at 12:00 am to identify a time entry 902 in thepredicted occupancy schedule 110.

At step 1414, the controller 102 updates the identified time entry 902in the predicted occupancy schedule 110 based on the determinedhistorical occupancy status 1508. Here, the controller 102 modifies orsets the identified time entry 902 in the predicted occupancy schedule110 with the determined historical occupancy status 1508 from step 1410.

At step 1416, the controller 102 determines whether there are any moreconflicting occupancy statuses 1506 to correct. Here, the controller 102determines whether all of the conflicting occupancy statuses 1506 thatwere identified in step 1406 have been corrected. The controller 102returns to step 1408 in response to determining that there are moreconflicting occupancy statuses 1506 to correct. In this case, thecontroller 102 returns to step 1408 to select another conflictingoccupancy status 1506 to repeat the correction process. Otherwise, thecontroller 102 may terminate method 1400. In this case, the controller102 determines that it has finished correcting any conflicting occupancystatuses 1506.

In one embodiment, the controller 102 may use the updated predictedoccupancy schedule 110 to retrain a machine learning model 112. Forexample, the controller 102 may use the updated predicted occupancyschedule 110 with a process similar to the process described in FIG. 7to retrain a machine learning model 112. Retraining the machine learningmodel 112 allows the controller 102 to improve the accuracy of themachine learning model 112 for future predictions.

Controller Hardware Configuration

FIG. 16 is an embodiment of a device (e.g. controller 102) configured tocontrol an HVAC system 104 using machine learning. The controller 102comprises a processor 1602, a memory 1604, and a network interface 1606.The controller 102 may be configured as shown or in any other suitableconfiguration.

The processor 1602 comprises one or more processors operably coupled tothe memory 1604. The processor 1602 is any electronic circuitryincluding, but not limited to, state machines, one or more centralprocessing unit (CPU) chips, logic units, cores (e.g. a multi-coreprocessor), field-programmable gate array (FPGAs), application specificintegrated circuits (ASICs), or digital signal processors (DSPs). Theprocessor 1602 may be a programmable logic device, a microcontroller, amicroprocessor, or any suitable combination of the preceding. Theprocessor 1602 is communicatively coupled to and in signal communicationwith the memory 1604. The one or more processors are configured toprocess data and may be implemented in hardware or software. Forexample, the processor 1602 may be 8-bit, 16-bit, 32-bit, 64-bit or ofany other suitable architecture. The processor 1602 may include anarithmetic logic unit (ALU) for performing arithmetic and logicoperations, processor registers that supply operands to the ALU andstore the results of ALU operations, and a control unit that fetchesinstructions from memory and executes them by directing the coordinatedoperations of the ALU, registers and other components.

The one or more processors are configured to implement variousinstructions. For example, the one or more processors are configured toexecute instructions to implement a HVAC control engine 1608. In thisway, processor 1602 may be a special purpose computer designed toimplement the functions disclosed herein. In an embodiment, the HVACcontrol engine 1608 is implemented using logic units, FPGAs, ASICs,DSPs, or any other suitable hardware. The HVAC control engine 1608 isconfigured to operate as described in FIGS. 1-15 . For example, the HVACcontrol engine 1608 may be configured to perform the steps of method200, 700, 1100, and 1400 as described in FIGS. 2, 7, 11, and 14 ,respectively.

The memory 1604 comprises one or more disks, tape drives, or solid-statedrives, and may be used as an over-flow data storage device, to storeprograms when such programs are selected for execution, and to storeinstructions and data that are read during program execution. The memory1604 may be volatile or non-volatile and may comprise read-only memory(ROM), random-access memory (RAM), ternary content-addressable memory(TCAM), dynamic random-access memory (DRAM), and static random-accessmemory (SRAM).

The memory 1604 is operable to store HVAC control instructions 1610,event data 114, machine learning models 112, occupancy history logs 602,predicted occupancy schedules 110, historical set point temperatureinformation 1202, and/or any other data or instructions. The HVACcontrol instructions 1610 may comprise any suitable set of instructions,logic, rules, or code operable to execute the HVAC control engine 1608.The event data 114, machine learning models 112, occupancy history logs602, predicted occupancy schedules 110, historical set point temperatureinformation 1202 are configured similar to the event data 114, machinelearning models 112, occupancy history logs 602, predicted occupancyschedules 110, historical set point temperature information 1202described in FIGS. 1-15 , respectively.

The network interface 1606 is configured to enable wired and/or wirelesscommunications. The network interface 1606 is configured to communicatedata between the controller 102 and other devices (e.g. HVAC system 104,thermostat 106, and devices 108), systems, or domain. For example, thenetwork interface 1606 may comprise a WIFI interface, a LAN interface, aWAN interface, a modem, a switch, or a router. The processor 1602 isconfigured to send and receive data using the network interface 1606.The network interface 1606 may be configured to use any suitable type ofcommunication protocol as would be appreciated by one of ordinary skillin the art.

HVAC System Configuration

FIG. 17 is a schematic diagram of an embodiment of an HVAC system 104configured to use machine learning. The HVAC system 104 conditions airfor delivery to an interior space of a building. In some embodiments,the HVAC system 104 is a rooftop unit (RTU) that is positioned on theroof of a building and the conditioned air is delivered to the interiorof the building. In other embodiments, portions of the system may belocated within the building and a portion outside the building. The HVACsystem 104 may also include heating elements that are not shown here forconvenience and clarity. The HVAC system 104 may be configured as shownin FIG. 17 or in any other suitable configuration. For example, the HVACsystem 104 may include additional components or may omit one or morecomponents shown in FIG. 17 .

The HVAC system 104 comprises a working-fluid conduit subsystem 1702 formoving a working fluid, or refrigerant, through a cooling cycle. Theworking fluid may be any acceptable working fluid, or refrigerant,including, but not limited to, fluorocarbons (e.g. chlorofluorocarbons),ammonia, non-halogenated hydrocarbons (e.g. propane), hydroflurocarbons(e.g. R-410A), or any other suitable type of refrigerant.

The HVAC system 104 comprises one or more condensing units 1703. In oneembodiment, the condensing unit 1703 comprises a compressor 1704, acondenser coil 1706, and a fan 1708. The compressor 1704 is coupled tothe working-fluid conduit subsystem 1702 that compresses the workingfluid. The condensing unit 1703 may be configured with a single-stage ormulti-stage compressor 1704. A single-stage compressor 1704 isconfigured to operate at a constant speed to increase the pressure ofthe working fluid to keep the working fluid moving along theworking-fluid conduit subsystem 1702. A multi-stage compressor 1704comprises multiple compressors configured to operate at a constant speedto increase the pressure of the working fluid to keep the working fluidmoving along the working-fluid conduit subsystem 1702. In thisconfiguration, one or more compressors can be turned on or off to adjustthe cooling capacity of the HVAC system 104. In some embodiments, acompressor 1704 may be configured to operate at multiple speeds or as avariable speed compressor. For example, the compressor 1704 may beconfigured to operate at multiple predetermined speeds.

In one embodiment, the condensing unit 1703 (e.g. the compressor 1704)is in signal communication with a controller 102 using a wired orwireless connection. The controller 102 is configured to providecommands or signals to control the operation of the compressor 1704. Forexample, the controller 102 is configured to send signals to turn on oroff one or more compressors 1704 when the condensing unit 1703 comprisesa multi-stage compressor 1704. In this configuration, the controller 102may operate the multi-stage compressors 1704 in a first mode where allthe compressors 1704 are on and a second mode where at least one of thecompressors 1704 is off. In some examples, the controller 102 may beconfigured to control the speed of the compressor 1704.

The condenser 1706 is configured to assist with moving the working fluidthrough the working-fluid conduit subsystem 1702. The condenser 1706 islocated downstream of the compressor 1704 for rejecting heat. The fan1708 is configured to move air 1709 across the condenser 1706. Forexample, the fan 1708 may be configured to blow outside air through theheat exchanger to help cool the working fluid. The compressed, cooledworking fluid flows downstream from the condenser 1706 to an expansiondevice 1710, or metering device.

The expansion device 1710 is configured to remove pressure from theworking fluid. The expansion device 1710 is coupled to the working-fluidconduit subsystem 1702 downstream of the condenser 1706. The expansiondevice 1710 is closely associated with a cooling unit 1712 (e.g. anevaporator coil). The expansion device 1710 is coupled to theworking-fluid conduit subsystem 1702 downstream of the condenser 1706for removing pressure from the working fluid. In this way, the workingfluid is delivered to the cooling unit 1712 and receives heat fromairflow 1714 to produce a treated airflow 1716 that is delivered by aduct subsystem 1718 to the desired space, for example a room in thebuilding.

A portion of the HVAC system 104 is configured to move air across thecooling unit 1712 and out of the duct sub-system 1718. Return air 1720,which may be air returning from the building, fresh air from outside, orsome combination, is pulled into a return duct 1722. A suction side of avariable-speed blower 1724 pulls the return air 1720. The variable-speedblower 1724 discharges airflow 1714 into a duct 1726 from where theairflow 1714 crosses the cooling unit 1712 or heating elements (notshown) to produce the treated airflow 1716.

Examples of a variable-speed blower 1724 include, but are not limitedto, belt-drive blowers controlled by inverters, direct-drive blowerswith electronically commutated motors (ECM), or any other suitable typesof blowers. In some configurations, the variable-speed blower 1724 isconfigured to operate at multiple predetermined fan speeds. In otherconfigurations, the fan speed of the variable-speed blower 1724 can varydynamically based on a corresponding temperature value instead ofrelying on using predetermined fan speeds. In other words, thevariable-speed blower 1724 may be configured to dynamically adjust itsfan speed over a range of fan speeds rather than using a set ofpredetermined fan speeds. This feature also allows the controller 1734to gradually transition the speed of the variable-speed blower 1724between different operating speeds. This contrasts with conventionalconfigurations where a variable-speed blower 1724 is abruptly switchedbetween different predetermined fan speeds. The variable-speed blower1724 is in signal communication with the controller 102 using anysuitable type of wired or wireless connection 1727. The controller 102is configured to provide commands or signals to the variable-speedblower 1724 to control the operation of the variable-speed blower 1724.For example, the controller 102 is configured to send signals to thevariable-speed blower 1724 to control the fan speed of thevariable-speed blower 1724. In some embodiments, the controller 102 maybe configured to send other commands or signals to the variable-speedblower 1724 to control any other functionality of the variable-speedblower 1724.

The HVAC system 104 comprises one or more sensors 1740 in signalcommunication with the controller 102. The sensors 1740 may comprise anysuitable type of sensor for measuring air temperature. The sensors 1740may be positioned anywhere within a conditioned space (e.g. a room orbuilding) and/or the HVAC system 104. For example, the HVAC system 104may comprise a sensor 1740 positioned and configured to measure anoutdoor air temperature. As another example, the HVAC system 104 maycomprise a sensor 1740 positioned and configured to measure a supply ortreated air temperature and/or a return air temperature. In otherexamples, the HVAC system 104 may comprise sensors 1740 positioned andconfigured to measure any other suitable type of air temperature.

The HVAC system 104 comprises one or more thermostats 106, for examplelocated within a conditioned space (e.g. a room or building). Athermostat 106 may be a single-stage thermostat, a multi-stagethermostat, or any suitable type of thermostat as would be appreciatedby one of ordinary skill in the art. The thermostat 106 is configured toallow a user to input a desired temperature or temperature set point fora designated space 122 or zone such as the room. The controller 102 mayuse information from the thermostat 106 such as the temperature setpoint for controlling the compressor 1704 and the variable-speed blower1724. The thermostat 106 is in signal communication with the controller102 using any suitable type of wired or wireless communications.

While several embodiments have been provided in the present disclosure,it should be understood that the disclosed systems and methods might beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

In addition, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component whetherelectrically, mechanically, or otherwise. Other examples of changes,substitutions, and alterations are ascertainable by one skilled in theart and could be made without departing from the spirit and scopedisclosed herein.

To aid the Patent Office, and any readers of any patent issued on thisapplication in interpreting the claims appended hereto, applicants notethat they do not intend any of the appended claims to invoke 35 U.S.C. §112(f) as it exists on the date of filing hereof unless the words “meansfor” or “step for” are explicitly used in the particular claim.

The invention claimed is:
 1. A heating, ventilation, and airconditioning (HVAC) control device, comprising: a memory operable tostore a predicted occupancy schedule for a space comprising a pluralityof time entries, wherein: each time entry is associated with a day ofthe week and an hour of a day; each time entry is associated with apredicted occupancy status; and each predicted occupancy status isassociated with a confidence level; and a processor operably coupled tothe memory, and configured to: receive a user input for controlling anHVAC system, wherein the user input comprises instructions for anoccupancy setting; determine whether the user input indicates an energysaving occupancy setting; identify a first plurality of time entriesthat are associated with a confidence level for a predicted occupancystatus that is less than a predetermined threshold value in thepredicted occupancy schedule; modify the predicted occupancy schedule bysetting the first plurality of time entries to an away status inresponse to determining that the user input indicates a first settingtype; modify the predicted occupancy schedule by setting the firstplurality of time entries to a present status in response to determiningthat the user input indicates a second setting type; and output themodified predicted occupancy schedule; wherein: each time entry in thepredicted occupancy schedule is associated with a predicted heating setpoint temperature; each predicted heating set point temperature isassociated with a second confidence level; the user input comprisesinstructions for an aggressive heating set point temperature setting;and the processor is further configured to: obtain historical set pointtemperature information for the space within a predetermined timeperiod, wherein the historical set point temperature informationcomprises a range of set point temperatures for the space during thepredetermined time period; determine a lowest set point temperature forthe space during the predetermined time period; identify a secondplurality of time entries that are associated with a second confidencelevel for a predicted heating set point temperature that is less than asecond predetermined threshold value in the predicted occupancy table;and modify the predicted occupancy schedule by setting the secondplurality of time entries with a predicted heating set point temperaturecorresponding with the lowest set point temperature.
 2. The device ofclaim 1, wherein outputting the modified predicted occupancy schedulecomprises operating the HVAC system in accordance with the modifiedpredicted occupancy schedule.
 3. The device of claim 1, whereinoutputting the modified predicted occupancy schedule comprises storingthe modified predicted occupancy schedule in the memory.
 4. A predictivetemperature scheduling method, comprising: receiving a user input forcontrolling an HVAC system, wherein the user input comprisesinstructions for an occupancy setting; determining whether the userinput indicates an energy saving occupancy setting; identifying a firstplurality of time entries that are associated with a confidence levelfor a predicted occupancy status that is less than a predeterminedthreshold value in a predicted occupancy schedule, wherein the predictedoccupancy schedule for a space comprises a plurality of time entries,wherein: each time entry is associated with a day of the week and anhour of a day; each time entry is associated with a predicted occupancystatus; and each predicted occupancy status associated with a confidencelevel; modifying the predicted occupancy schedule by setting the firstplurality of time entries to an away status in response to determiningthat the user input indicates a first setting type; modifying thepredicted occupancy schedule by setting the first plurality of timeentries to a present status in response to determining that the userinput indicates a second setting type; and outputting the modifiedpredicted occupancy schedule; wherein: each time entry in the predictedoccupancy schedule is associated with a predicted heating set pointtemperature; each predicted heating set point temperature is associatedwith a second confidence level; the user input comprises instructionsfor an aggressive heating set point temperature setting; and furthercomprising: obtaining historical set point temperature information forthe space within a predetermined time period, wherein the historical setpoint temperature information comprises a range of set pointtemperatures for the space during the predetermined time period;determining a lowest set point temperature for the space during thepredetermined time period; identifying a second plurality of timeentries that are associated with a second confidence level for apredicted heating set point temperature that is less than a secondpredetermined threshold value in the predicted occupancy table; andmodifying the predicted occupancy schedule by setting the secondplurality of time entries with a predicted heating set point temperaturecorresponding with the lowest set point temperature.
 5. The method ofclaim 4, wherein outputting the modified predicted occupancy schedulecomprises operating the HVAC system in accordance with the modifiedpredicted occupancy schedule.
 6. The method of claim 4, whereinoutputting the modified predicted occupancy schedule comprises storingthe modified predicted occupancy schedule in the memory.
 7. Anon-transitory computer readable medium storing instructions that whenexecuted by a processor cause the processor to: receive a user input forcontrolling an HVAC system, wherein the user input comprisesinstructions for an occupancy setting; determine whether the user inputindicates an energy saving occupancy setting; identify a first pluralityof time entries that are associated with a confidence level for apredicted occupancy status that is less than a predetermined thresholdvalue in a predicted occupancy schedule, wherein the predicted occupancyschedule for a space comprises a plurality of time entries, wherein:each time entry is associated with a day of the week and an hour of aday; each time entry is associated with a predicted occupancy status;and each predicted occupancy status associated with a confidence level;modify the predicted occupancy schedule by setting the first pluralityof time entries to an away status in response to determining that theuser input indicates a first setting type; modify the predictedoccupancy schedule by setting the first plurality of time entries to apresent status in response to determining that the user input indicatesa second setting type; and output the modified predicted occupancyschedule; wherein: each time entry in the predicted occupancy scheduleis associated with a predicted heating set point temperature; eachpredicted heating set point temperature is associated with a secondconfidence level; the user input comprises instructions for anaggressive heating set point temperature setting; and further comprisinginstructions that when executed by the processor causes the processorto: obtain historical set point temperature information for the spacewithin a predetermined time period, wherein the historical set pointtemperature information comprises a range of set point temperatures forthe space during the predetermined time period; determine a lowest setpoint temperature for the space during the predetermined time period;identify a second plurality of time entries that are associated with asecond confidence level for a predicted heating set point temperaturethat is less than a second predetermined threshold value in thepredicted occupancy table; and modify the predicted occupancy scheduleby setting the second plurality of time entries with a predicted heatingset point temperature corresponding with the lowest set pointtemperature.
 8. The non-transitory computer readable medium of claim 7,wherein outputting the modified predicted occupancy schedule comprisesoperating the HVAC system in accordance with the modified predictedoccupancy schedule.